Mat



FIG. 1 is a front/right/top perspective view of a mat (a front/left/top perspective view would be a mirror image thereof);

FIG. 2 is a front/left/top perspective view thereof at a different angle (a front/right/top perspective view would be a mirror image thereof);

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom plan view thereof; and,

FIG. 5 is a right side elevational view thereof.

The broken lines depict environment and form no part of the claimed design. 

CLAIM I claim the ornamental design for a mat, as shown and described. 